1. Field of the Invention
This invention relates to methods and devices for generating high-pressure fluid jets, and more particularly, to methods and devices for generating fluid jets having a controlled level of coherence.
2. Description of the Related Art
Conventional fluid jets have been used to clean, cut, or otherwise treat substrates by pressurizing and focusing jets of water or other fluids up to and beyond 100,000 psi and directing the jets against the substrates. The fluid jets can have a variety of cross-sectional shapes and sizes, depending upon the particular application. For example, the jets can have a relatively small, round cross-sectional shape for cutting the substrates, and can have a larger, and/or non-round cross-sectional shape for cleaning or otherwise treating the surfaces of the substrates.
One drawback with conventional fluid jets is that they may tear or deform certain materials, such as fiberglass, cloth, and brittle plastics. A further drawback is that the effectiveness of conventional fluid jets may be particularly sensitive to the distance between the substrate and the nozzle through which the fluid jet exits. Accordingly, it may be difficult to uniformly treat substrates having a variable surface topography. It may also be difficult to use the same fluid jet apparatus to treat a variety of different substrates. Still a further disadvantage is that some conventional fluid jet nozzles, particularly for non-round fluid jets, may be difficult and/or expensive to manufacture.
Accordingly, there is a need in the art for an improved fluid jet apparatus that is relatively simple to manufacture and is capable of cutting or otherwise treating a variety of substrates without being overly sensitive to the stand-off distance between the nozzle and the substrate. The present invention fulfills these needs, and provides further related advantages.